Hepatocellular carcinoma in a sheep

At necropsy of a five-year-old sheep, a pear shaped, lobular yellow-brownish mass measuring about 12 × 15 × 20 cm was found to involve the right hepatic lobe. Microscopic examination revealed two trabecular and solid patterns of neoplastic hepatocytes. In solid pattern, there were numerous tumoral giant cells that contain one or more large hyperchromatic bizarre-shaped nuclei scattered among clusters of neoplastic hepatocytes. In addition, mitotic figures, dilated sinusoids and large vascular spaces filled with red blood cells were observed in some sections. Based on gross and histopathologic characteristics, the mass was diagnosed as hepatocellular carcinoma.